SAN DIEGO — Late-summer dry thunderstorms rolled into California from the southwest desert region early Sept. 2, bringing thousands of lightning strikes and increasing the risk of wildfires as high temperatures lingered in parts of the state. Shortly before 3 a.m. local time on Sept. 2, theNational Weather Service office in the San Francisco Bay Areareported that numerous fires appeared to have ignited "during the past hour as a result of lightning in extreme" southeast Monterey County and southwest Fresno County. The agency noted that winds in the area had been light but fuels in the area remained very dry. The weather service later reported that between midnight and 5:30 a.m. local time, nearly 4,800 total lightning strikes were recorded, including in-cloud and cloud-to-ground lightning. Lightning data shared by the weather service showed that the lightning strikes were concentrated in areas between the inland East Bay and the Central Valley. "'Dry' thunderstorms rolled through the Central Valley and portions of the East Bay this morning. Most areas saw less than 0.10" inches of rain & there were a few fire starts," the weather service said ina post on X. Shortly after the thunderstorms moved through the region, the California Department of Forestry and Fire Protection (Cal Fire) reported over a dozen new wildfires. The causes for the blazes remained under investigation, according to Cal Fire. The dry thunderstorms come amid a lingering heat wave in Southern California and scorching temperatures in other parts of the state. Fire risks have been heightened across the state over the summer as high temperatures, along with dry winds and low humidity, fueled conditions forgrowth on existing and new fires. Theweather service office in Los Angeleswarned that while temperatures were expected to drop over some areas on Sept. 3, the weather will remain "very warm." Heat advisories issued from areas between inland San Luis Obispo County and San Diego County expired by 6 p.m. local time Sept. 2, while advisories for areas between inland Ventura County and Orange County remain in effect until Sept. 3. US wildfire, smoke map:Track latest wildfires, red flag warnings Daniel Swain, a climate scientist with the University of California, Los Angeles,said on Xthat a "significant" and "rapidly unfolding" lightning-induced wildfire outbreak was underway in the central and southern Sierra Nevada mountains. The outbreak is mainly impacting the Sierra Nevada Foothills, according to Swain. At around 12 p.m. local time Sept. 2, Swain reported that dozens of new lightning ignitions had already occurred in the region "with new reports coming in every (five minutes)." More lightning was also forecast for later in the day. The weather service had issued severe thunderstorm warnings through the afternoon of Sept. 2 for some portions of the Central Valley and Southern California. Ared flag warningfor parts of Northern California near the Oregon border was also issued on Sept. 2 due to "abundant lightning on dry fuels," according to the weather service. "Scattered thunderstorms with abundant lightning possible," the weather service said in its advisory. "Storms may produce little or no rain, and lightning strikes outside of precipitation cores are possible, and may cause many new fire starts." ABC10 Sacramento reportedon Sept. 2 that firefighters with the Sacramento Metropolitan Fire District responded to five wildfires after more than 60 lightning strikes hit east of Sloughhouse, a community in southeast Sacramento County. Captain Mark Nunez, spokesperson for Sacramento Metropolitan Fire District, told the television station that the lightning strikes had contributed to the ignition of the blazes. Hurricane Kiko forms in the Pacific:See path tracker, forecast. Dry lightning occurs during"dry thunderstorms,"which produce little to no rainfall. On Sept. 2, across California, the rain evaporated in dry air before reaching the ground, according to the weather service,adding: "most areas saw less than 0.10" inches of rain & there were a few fire starts." Wildfires are a real concern with dry lightning. According to the weather service, the drier the storm and the drier the vegetation, the more likely lightning strikes are to spark wildfires. That's because cloud-to-ground lightning can easily ignite parched fuel without rain to help dampen it. Lightning-caused wildfiresare much larger and consume more land than human-caused fires — 53% of the average acreage burned from 2018 to 2022, theUSA TODAY Network reported. But the majority of wildfires are caused by humans, with 89% of the average number of wildfires from 2018 to 2022. During the summer of 2020, a lightning storm ignited numerous wildfires across California.USA TODAY previously reportedon Aug. 24, 2020, that more than 13,000 lightning strikes — which sparked hundreds of blazes — had been recorded since Aug. 15, 2020. Contributing: Doyle Rice, USA TODAY; Brandi D. Addison, USA TODAY Network This article originally appeared on USA TODAY:Thousands of lightning strikes hit California increasing wildfire risk
